A Three-Dimensional Coordination Framework with a Ferromagnetic Coupled Ni(II)-CrO 4 Layer: Synthesis, Structure, and Magnetic Studies

We report herein on the crystal structure and magnetic studies of a three-dimensional (3D) Ni(II)-chromate coordination polymer, [Ni(CrO )(bpym)(H O)] ( ; bpym = 5,5'-bipyrimidin), prepared by self-assembly of Ni(II) and chromate ions with a multi- donor auxiliary ligands, bpym, through hydrothermal processes. The structure of is composed of Ni(II)-CrO layers with [Ni ( -CrO )] triangular motifs, in which the Ni(II) centers are bridged by ': ': ': -CrO anions, and the resulting layers are further connected by twisted - - , '-bpym auxiliary ligands to form a 3D pillar-layered network with an topology. The magnetic properties of compound were illustrated by variable field and temperature magnetic susceptibility measurements. The findings reveal that compound shows intralayer ferromagnetic interactions within Ni(II)-CrO layers, and furthers the 3D antiferromagnetic ordering in the resulting of interlayer antiferromagnetic couplings with a Néel temperature ( ) of 5.6 K. In addition, compound shows the field-induced metamagnetic behavior at temperature below the .